In some surgical procedures metallic inserts are inserted into a patients body for the purpose of repairing severe bone fractures and breakages caused, for example, in vehicle accidents. One group of such inserts include metal pins, or cylindrical bars. After implantation one or more locking holes are drilled through the biological tissue structure (skin, fat, bone, etc.) at the distal and proximal ends for the purpose of securing the inserts. Normally, the location, drilling, and locking of proximal holes in the insert is not a major technical challenge, but distal hole interlocking of the inserts is a highly specialised and technically demanding procedure, particularly when it comes to the placement of distal locking screws through a locking hole in the metal inserts.
Traditional techniques for distal locking of inserts include the use of mechanical jigs and the free hand technique, and X-ray machines. The mechanical method is prone to providing inaccurate information and a common problem experienced by surgeons is that once a hole has been inaccurately drilled it is virtually impossible to drill a second hole since the correct position of the hole is normally very close to the existing hole, thus causing the drill to slip and follow the path of the first hole. The use of X-ray machines is time consuming, requires specialised personnel to operate, and presents a risk of staff/patient exposure to potentially harmful doses of ionised radiation.
Distal interlocking is acknowledged as being the most difficult part of the insert insertion procedure. When difficulties are encountered in such a procedure X-ray screening times (exposure to the patient and the surgical team) can be greater than ten minutes, and the operating time can be greater than one hour. Difficulties often arise due to the fact that the radiographer is unable to provide the surgeon with the required image. This is often due to the fact that the surgeon is unable to manipulate the X-ray machine to produce the required image because the machine is not sterile and is cumbersome to use, thus it is physically impossible to place the X-ray head close to the fracture site.